Bolt anchor



June 14, 1938.

G. O. HIERS BOIJT ANCHOR Filed Dec. 20, 1955 INVENTOR .Jww 1 MATT oRNEYs.

Patented June 14,

UNITED STATES PATENT OFFICE 2,120,219 noL'r' ANCHOR Application December 20, 1935, Serial No. 55,320

12 Claims.

The invention relates to expanded lead anchorages, the object being to improve their holding power in relation to their size and consists in the application of an obturating ring to the members constituting the anchorage as hereinbelow more fully explained.

The accompanying drawing illustrates one of various possible forms of the invention, being the preferred form. Fig. 1 is an axial section of the anchorage prior to caulking; Fig. 2 the same after caulking; Fig. 3 the same anchorage modifled to receive the threaded end of the bolt; Fig.

4 a detail of the obturating ring; and Fig. 5 a perspective of the unit assembly.

The obturating ring is marked I and is applied to the member of the anchorage that is to be confined by the caulked lead in the drilled hole, that is to say, in the present case, to a hard metal, or iron collar 2 which is placed on the bolt 3, against its head 4. Such member, within this invention, can be constituted of any suitable enlargement fast to the bolt and adapted to be bottomed in the drilled anchor hole 5 and then confined therein by the caulking, and it may therefore be either a collar as shown, or a part of the bolt-head 4 itself or it may bea nut on the bolt, as shown in Fig. 3, presently described.

The obturating ring I, is situated between the enlargement and the mass 6 of the lead or caulking material and is designed to be expanded within the hole until it more or less closes the annular crevice between the enlargement ancl the wall of the hole. By such closure or partial closure, the relatively mobile lead under the pressure of the load on the bolt 3 is prevented from flowing or escaping through such crevice, with the effect of greatly improving the holding power, improvements of the order of20%havingbeenconsistently obtained, and with the further effect of accommodating the anchorage to holes that have been drilled somewhat too large, without loss of holding power. a

It is preferred to spread or expand the obturating ring by making the bolt enlargement 2 tapered or in the form of a cone and by forcing the ring on to it by the pressure of the lead againstthe ring under the action of the caulking tool, shown in dotted lines at I. but the principle of the invention is independent of any particular means of spreading the ring, whether done by the movement of the ring on a stationary cone or the reverse, or in some other-way. In the case in hand the cone 2 is provided with flutes 8 (Fig. 5) and, in consequence, the lead under-the caulking pressure has some access to the inner surface of the ring and, pressing outwardly thereon. assists in its expansion, so that it is proper to say. in the case illustrated, that the lead acts both directly and indirectly to produce the expansion of the ring. I 5

It is not required that the obturating ring shall expand into actual engagement with the wall of the drilled hole, although that is desirable. Any reduction of the cross area of the possible escape path for the lead over or past the bolt en- 10 largement is found to improve the holding power.

In Fig. 3, the same members as'in Figs. 1 and 2 are modified to take the threaded end of the bolt, the bolt enlargementin this case, marked 9, being internally threaded to serve as the nut for the bolt and also chambered to provide clearance for the bolt end.

The obturating ring is rendered expansible by allowing it either to stretch or break, as the result of the circumferential strain exceeding its tensile limit, or it may be initially split, if desired, or it may be furnished with a line of weakness on which it will part under the strain. It is preferable in any case that its expansion results in no gap or break in its circumferential g5 continuity through which lead under pressure might flow or squeeze and on this account when the line of weakness is used it is preferably located obliquely as indicated at III in Fig. 4; When the ring parts on this line the ends form a scarfed joint which does not open up an escape for the lead. The metal of the ring is harder or less mobile than lead and its dimensions are predetermined with relation to its material so that it will perform its expansion before or as the lead begins to flow under the caulking iron thus insuring that the crevice is promptly closed and the lead not likely to escape even during caulking. This relation is important and is brought about by the position and shape and also the extent of the area of the outwardly facing side of the ring, that is exposed to the pressure of the caulking material. The whole, or at least the greater part of this face of the ring, is either flat or normal to the" direction of pressure, or dished or otherwise shaped so as to minimize the tendency for the lead to flow over and around the ring's cylindrical exterior, at least until the ring I has .been driven to its maximum expansion and the crevice between the bolt enlargement and anchor hole reduced to its minimum.

The ring has considerable axial dimension, at least equal to its radial thickness and desirably, it is internally bevelled and at about the same angle as the taper of the cone on which it rides.

This facilitates the expansion and keeps the ring normal to the bolt axis during caulking and more especially, when the bolt is under strain, it facilitates transmission of some of the pressure radially outward, pressing the hard metal ring against the wall of the hole, thus enhancing the friction which the unit as a whole has upon that wall. The'proportions referred to give the ring a relatively long bearing on the cone 2 as well as on the wall of the hole so that its peripheral cylindrical surface is kept at all times parallel to the wall of the hole.

Desirably also, the annular members of the anchorage are united in some way at the time of manufacture so that they can be packed, sold and handled as a unit. It is found that by forming an annular rebate in the ring as indicated at II and pressing the lead annulus firmly into it, a sufficiently secure attachment is produced between these parts, notwithstanding that the side of the annular groove ll may flare outwardly as indicated in the drawing. This also aids to some extent in reducing or retarding the tendency of the lead to flow around the cylindrical periphery of the ring before its expansion is completed. The cone also can be securely attached to the obturating ring by initially pressing it or starting it on the cone. This can be done with the kerfed rings without rupturing or appreciably stretching them and forms a practical attachment notwithstanding the taper, so that all three members can thus be united in simple manner to form a single sales unit which has a general appearance shown by Fig. 5 and which will stay in unit form under all normal conditions of shipment and use. As facilitating this attachment the small end of the coned collar 2 may have a less taper than its wider part. This double taper is shown in the drawing, but the ring can also be otherwise or additionally locked to the cone if desired.

The provision of the flutes 8 on the coned surface of the collar serves the additional function of preventing, or assisting in preventing, the rotation of the unit with relation to the drilled hole when the bolt of Fig. 1 is having its external nut screwed on to it or when the unit includes the nut for the bolt as in Fig. 3.

From the description above given, it will now be apparent that the principle of the invention can be applied in various ways and with component members of different shapes and relation, and that one or more of the adjunctive features above described can be employed with it as desired, there being no intention to limit the scope of this patent to any particular type or design except as pointed out in the claims hereof.

I claim:

1. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held thereon by a body of caulking material, the improvement which consists in said ring having an interior surface adapted to ride on the taper of said enlargement and an exterior surface adjacent and parallel to the wall of said anchor hole, said surface being of substantially cylindrical form adapted for making a surface contact with said wall as the ring expands, the outwardly facing side of the ring that is exposed to the pressure of the caulking material being substantially normal to the axis of the bolt.

2. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held thereon by a body of caulking material, the improvement which consists in said ring having a substantially cylindrical peripheral surface which is longer, axially, than the radial thickness of the ring and a tapered internal surface also longer than said thickness adapted to ride on said enlargement, the outwardly facing side of the ring that is exposed to the pressure of the caulking material being substantially normal to the axis of the bolt.

3. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held thereon by a body of caulking material, the improvement which consists in said ring having its outwardly facing side arranged substantially normal to the bolt axis to receive the pressure of the caulking material, and having a portion of its internal surface opposed to said enlargement and accessible to said pressure of the caulking material for assisting in the expansion of said ring.

4. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held thereon by a body of caulking material, the improvement which consists in said ring having its axial dimension longer than its radial thickness, its interior surface also longer than said thickness and its outwardly facing side, that is exposed to the pressure of the caulking material, disposed in a position substantially normal to the axis of the bolt, and said tapered enlargement being fluted for transmitting caulkin pressure to the interior of the ring.

5. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held therein by a body of caulking material, the improvement which consists in said enlargementbeing fluted and said ring having its outwardly facing surface in contact with and subject to axial pressure exerted by the caulking material and its internal surface exposed through the flutings of said enlargement to expanding pressure from the caulking material.

6. In anchorages of the kind comprising a tapered collar to be received on a bolt and confined in the anchor hole and an expansible obturatin'g ring expanded by being driven onto the collar and held thereon by a ring of caulking lead, the improvement which consists in said tapered collar being fluted and both said rings being arranged and mounted for axial movement upon and along the fluted surface thereof.

7. In anchorages of the kind comprising a tapered bolt enlargement to be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the enlargement and held thereon by a body of caulking material, the improvement which consists in said ring having its peripheral surface substantially cylindrical and of substantially greater axial length than the radial thickness of said ring, and a recess in the side of said ring that is exposed to the caulking pressure, said recess receiving the caulking material and presenting an inwardly facing surface subject to the expanding pressure thereof.

8. In anchorages of the ldnd comprising a tapered collar adapted to be received on a bolt I and be confined in the anchor hole and an expansible obturating ring expanded by being driven onto the taper and held on the collar by a body of caulking lead, the improvement which consists in said ring having a scarf joint permitting its expansion without opening a passage through it and having substantially the whole of its outwardly facing surface substantially normal to the axial pressure exerted by the caulking material.

9. The construction of the preceding claim wherein the ring is formed with an oblique line of weakness adapted to form said scarf joint when it is ruptured by the expansion.

10. In anchorages of the kind described, a

being frictionally held on the smaller end of said collar to form a sales unit of said parts.

11. In anchorages of the kind comprising a tapered collar for assembly on a bolt and to be 12. In anchorages of the kind described, a

tapered collar for assembly on a bolt and to be confined in the anchor hole and an expanding obturating ring expanded by being driven onto the collar and held thereon by-a ring of caulking lead, the improvement which consists of said obturating ring having an internal surface to ride on the taper of said collar and the exterior cylindrical surface initially of no greater diameter than said collar and extending parallel to the wallof the anchor hole for making a surface contact with said wall as the ring expands, one of said rings being held on the small end of said collar to form a sales unit of said parts.

GEORGE o. HIEARS- 

